Marvin
Marvin is a metaphor for Nixon himself. Indeed, even his name is written like Nixon’s – the name Marvin K. Mooney can be directly referenced to Richard M. Nixon. His reluctance to leave the house is a metaphor for Nixon’s delay and reluctance in giving up his own presidential role.
Different choices
The fact that the reader is shown all of the different ways Marvin can leave is Seuss’ way of telling children that they have a choice in matters of life. They can choose a variety of options but ultimately, have to take responsibility and make one final choice.
Marvin Walking
Despite the fact that the narrator gives a whole variety of options for Marvin to make his exit, he eventually chooses to walk away. This is perhaps a reference to Nixon’s own leave – he was known to be a highly prideful man, and so this may be a reference to him leaving in a dignified way before the people could push him out.